Table 2. Phenotypic non-susceptibility of ESBL producing E. coli from recreational water (N = 82) and wastewater (N = 91) compared to strains from urine (N = 94).
| Urine % | Water % | p | Wastewater % | p | |
|---|---|---|---|---|---|
| Ampicillin | 100 | 100 | 1 | 991 | 1 |
| Cefuroxime | 100 | 991 | 1 | 991 | 1 |
| Cefotaxime | 99 | 98 | 1 | 96 | 0.21 |
| Aztreonam | 98 | 85 | 0.03 | 85 | 0.007 |
| Ceftazidime | 85 | 77 | 0.06 | 66 | 0.001 |
| Trimethoprim | 77 | 51 | 0.002 | 66 | 0.09 |
| Trimethoprim-sulfamethoxazole | 72 | 50 | 0.008 | 62 | 0.1 |
| Ciprofloxacin | 69 | 35 | 0.001 | 42 | 0.001 |
| Gentamicin | 34 | 20 | 0.03 | 34 | 0.8 |
| Mecillinam | 3 | 0 | 1 | 6 | 0.5 |
| Piperacillin-tazobactam | 5 | 5 | 0.48 | 7 | 1 |
| Nitrofurantoin | 1 | 0 | 1 | 7 | 0.09 |
| Meropenem | 0 | 0 | - | 0 | - |
| Multidrug-resistance2 | 88 | 52 | 0.001 | 68 | 0.001 |
1100% non-susceptibility would be expected as the isolates initially grew on selective media, and contain ESBLs according to initial tests and DNA-analysis. The wastewater isolate which was susceptible to ampicillin and cefuroxime contained blaCMY-58. The isolates from recreational water which were susceptible to cefuroxime both contained blaSHV-12.
2Resistance to ≥ 2 different antibiotic classes other than β-lactams.